A database is a collection of stored data that is logically related and that is accessible by one or more users or applications. A popular type of database is the relational database management system (RDBMS), which includes relational tables, also referred to as relations, made up of rows and columns (also referred to as tuples and attributes). Each row represents an occurrence of an entity defined by a table, with an entity being a person, place, thing, or other object about which the table contains information.
One of the goals of a database management system is to optimize the performance of queries for access and manipulation of data stored in the database. Given a target environment, an optimal query plan is selected, with the optimal query plan being the one with the lowest cost, e.g., response time, as determined by an optimizer. The response time is the amount of time it takes to complete the execution of a query on a given system.
In computer systems featuring a plurality of hard disks, contiguous areas of storage space of a hard disk or other storage medium, e.g., extents, may be allocated based on a least disk utilized algorithm where the disk with the highest free percentage is used as the target device for the next algorithm. In a system with non-skewed balanced nodes, least disk utilization algorithms generally perform satisfactorily. However, in systems featuring node skew, such mechanisms may result in undesirable system performance.